Thermionic tube and circuit



Sept. 21, 1937.

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RFC Prc HEATER 5405 NILS E. LINDEN BLAD 'INVENTOR Patented Sept. 21,1937 THERMIONIC TUBE AND CIRCUIT Nils E. Lindenblad, Port .'Ieierson, N.Y., assigner ,l

to Radio Corporation of America, a corporaf tion of Delaware ApplicationMarcela, 1935, serial No. 10,772

6 Claims.

Thisl invention relates to a new thermionic tube and to said novel tubein connection with circuits particularly` adapted to derive from saidnovel tube optimum operation.

It is well known that the higher the frequency becomes the lower thecapacitive reactance between the elements in a vacuum tube subject tosaid high frequency becomes. Accordingly, the intensity of the highfrequency oscillating currents will become higher and higher as thefrequency of oscillation increases in order to maintain the properoscillating voltage necessary between electrodes for the functioning ofthe tube.

I For ordinary short wave needs, this trouble may to` a certain extentbe remedied by making lthe leads or conductors connected with the tubeelements of large cross-section area to accommodate the increasedcurrent. For still shorter Waves, it becomes increasingly diiiicult toincrease the dimensions of these conductors or leads any further becauseof the cumbersome glass seals required for such heavy leads. To overcomethis defect, I propose to make it possible to obtain the radio frequencyconnection between the tube elements and the external circuits by meansof a capacitive coupling. 'I'hisrpermits me to use small conductorsleading from elements in the tube through the vitreous envelope, tosupply to said elements the necessary direct current potentials, keepingin mind that current of small intensity is usually suiiicient foroperation.

In disclosing the invention, for purposes of illustration I have shown anovel circuit arrangement particularly applicable to the tube of theinvention. However, I do not intend to limit this disclosure to the useof such a circuit with my novel tube, since obviously the Vtube of thepresent invention is applicable to practically any use known in theradio art. The tube of my invention is particularly adapted 'to shortradio frequency waves. The tube may be used in ultrahigh frequency relaycircuits in which oscillations are relayed, amplified, relayed andamplified, frequency multiplied, amplified and frequency multiplied,etc. The tube is particularly adapted to use in circuits for producingultra-high frequency waves.

In further describing my invention, reference will be made tothedrawing, in which:

Fig. 1 shows diagrammatically a tube, the electrodes of which arearranged in accordance with my invention. The electrodes of the tubes inFig. 1 are also connected in novel alternating current circuits anddirect current supply circuits.

Fig. 2 shows a modification of the electron (Cl. Z50-36) emissionelectrode structure of the tube of Fig. 1.

Referring to the drawing, each thermionic tube may comprise an envelope2 enclosing a thermionic system including an emission electrode 4, acontrol electrode 6 and an anode electrode 8. The vitreous envelope 2may have a main body in which said thermionic system is located and fromwhich elongated portions extend. Each of the electrodes 4, 6 and 8 lareconnected with con` ducting rnemberswhich` extend out to differentelongated portions of the tube. The emission electrode 4 is connected by.leads extending through the vitreous envelope of the tube to atransformer T which may be connected toa source of energizing current.filament energizing circuit is connected l,directly to a conductiveVmember lil located within the envelope. The `other side of the filamentheating circuit is connected by a condenser I2, of low impedance to highfrequency waves, to said member I Il. The anode and control gridelectrodes are in a similar manner Aconnected by heavy conductingmembers to large surface conductors I4 and I6, respectively, located inextended portions of the envelope. In order to apply the necessarybiasing potential to the control grid I4, IV pass a small conductor fromthe enlarged metallic portion I4 through the tube envelope and connectthis lead by way of a radio frequency choke RFC land biasing resistanceR to a source C and to ground.` In order to supply the necessarycharging potentials to the anode electrode 8, a conductive lead ispassed from the member I6 through the tube envelope and by way of aradio frequency choke RFC to a direct current source One side of the land to ground. Since, as shown in the drawing,

the large conducting portions andthe members I4 and I6 extend away fromthe control grids 6 and 8, respectively, the internal capacity betweenthe electrodes is not materially increased by my novel tube structure.

In order to connect the electrodes of the tube disclosed in analternating current circuit, I provide sleeve members I8, Ztl and 22,respectively, located on the outer periphery of each tube envelopeadjacent the conducting members Ill, I4 and I6, respectively. The threeexternal sleeve members are then connected in alternating currentcircuits 24, 26 and 28, respectively, as shown, the circuits beingcompleted by way of the capacities formed between the elements I0 andI8, I4 and 2B, and I6 and 22, respectively. The capacity reactancebetween the elements I0, I8 I4, 20 and IB, 22 may be maintainedsufficiently low to have negligible radio frequency volt-age drops. The

alternating current circuits 24, 26 and 28 may be utilized as above toamplify, multiply or produce -alternating current potentials.

In some cases, it may be preferable to use a thermionic tube of thecathode heater type. This permits the emission element to beconvenientlyl extended in the opposite direction from the grid electrodeelement. This emission element may take the form of a sleeve and mayAalso carrythe heavy high frequency current which at times falls upon thelament of the directly heater or indirectly heated tube. Such astructure has been illustrated in Fig. 2, wherein thecathode is heatedindirectly by a heater element connected by leads to a source of heatingcurrent. The emission element may be connected to a sleeve in turnconnected directly to an enlarged member I O coupled to I8.

What is claimed is:

1. In a discharge tube, a container h-aving a sleeve-like portion foreach electrode of the thermionic system and a main portion from whichsaid sleeve-like portions extend, an electron system having a pluralityof electrodes arranged in said main portion, conductors extending fromeach electrode of said system to -a diierent one of said sleeve-likeportions, conducting members of appreciable area connected to each ofsaid conductors, each of said conducting members being located withinthe inner periphery of its respective sleeve-like portion, andconducting members located on the outer periphery of each of saidsleeve-like portions.

2. In a discharge tube, a container having a sleeve-like portion foreach electrode of the thermionic system and a main portion from whichsaid sleeve-like portions extend, an electron system including aplurality of electrodes arranged in said main portion, conductorsextending from each electrode of said system to a different one of saidsleeve-like portions, a conducting member of appreciable surfaceconnected to each of said conductors, said conducting members each beinglocated within the inner periphery of its respective sleeve-likeportion, and conducting members located on the outer periphery of eachof said sleeve-like portions whereby alternating current circuits may becoupled between the electrodes of said tube by Way of the couplingbetween the conducting members on the inner and outer peripheries ofsaid cylindrical portions.

3. In a discharge tube system, a container having a main portion and anextended portion for each electrode of the thermionic system, anelectrode system of the multi-electrode type arranged in said mainportion, conductors extending from each electrode of said system to adifferent one of said extended portions, an enlarged sleeve memberconnected to each conductor and located within the inner periphery ofthe respective extended portions, conducting members located on theouter peripheryof each of said extended portions, and alternatingcurrent circuits coupled between said outer conducting members.

4. In a discharge tube system, a container having a main body and anextended portion for each electrode of the thermionic system, amulti-electrode system arranged in said main body, conductors extendingfrom each electrode of said system to a different one of said extendedportions, an enlarged member connected to each conductor and locatedwithin the inner periphery of the respective extended portions, a leadpassing from each enlarged member through the envelope of saidcontainer, sleeve-like members located on the outer periphery of each ofsaid portions, alternating current circuits coupled between said outersleeve-like members, and direct current circuits connected between theleads passing through the envelope of the container.

5. In a discharge tube system, a container having a cylindrical portionfor each electrode of the thermionic system and a main portion, amultielectrode system arranged in said main portion, conductorsextending from each electrode of said system to a different one of saidcylindrical portions, an enlarged cylindrical sleeve connected to eachconductor and located within the inner periphery of the cylindricalportions, a lead passing from each cylindrical sleeve member through theenvelope of said container, cylindrical sleevelike members located onthe outer periphery of each of said cylindrical portions, alternatingcurrent circuits coupled between said outer sleevelike members, anddirect current circuits connected with the conductors passing throughthe container.

6. In an ultra high frequency signalling system, a plurality of electrondischarge devices each comprising a container enclosing an anode, acathode and a control grid electrode, a conducting member ofconsiderable larea connected to each electrode in each device andlocated adjacent the inner wall of the container of said device,corresponding conductive members of considerable area located adjacentthe outer wall of the container of each of said devices and coupled tosaid rst named members, there being a conducting member adjacent theouter wall of the container of each device for each conducting memberadjacent the inner wall of the container of each device and reactancesconnecting corresponding conducting members radjacent the outer Walls ofthe containers of said devices together to thereby couple correspondingelectrodes of said devices in ultra high frequency circuits.

NILS E. LINDENBLAD.

